1. Field of the Invention
This invention relates to joints, especially at the shoulder or hip, of hard space suits. It may also be used on diving suits, manipulator arms, user-occupied arms for penetrating boxes such as autoclaves, high-vacuum boxes for integrated circuit work and the like, and to cover and isolate articulated torque drives which require protection from hostile environments. The joint has an outer covering of a relatively rigid material comprising plural sections which may rotate relative to each other through 360.degree. while maintaining an airtight seal. In the preferred embodiment, there are also inner covering sections of flexible material such as bellows, corresponding to at least some outer covering sections which do not rotate relative to each other.
2. Description of Prior Art
A description of prior art is set forth in U.S. Pat. No. 4,091,464. The present invention distinguishes over the prior art listed therein and from U.S. Pat. No. 4,091,464 in a number of respects. The named reference shows sections of flexible fabric connected at joints whereby larger dimensioned sections are joined to sections of smaller dimensions. The joints pivot about axes. Each joint has a ball bearing having inner and outer races, the outer race being fixed to the larger section and the inner race being fixed to the smaller section. The construction of the joints of this reference, however, result in considerable friction resisting relative movement.
U.S. Pat. No. 3,782,481 shows a continuous bellows outer layer which provides a hermetic seal plus two inner layers, each of which comprises alternate rigid cylindrical wedges and bellows. The innermost and next innermost layers alternate--i.e., if there is a bellows section at one portion of the innermost layer, which is always encircled by a cylindrical wedge section of the next innermost layer. Since the two inner layers must be able to transmit torque from one end to the other, the wedge sections of these inner layers cannot rotate independently of adjacent bellows sections. This feature of U.S. Pat. No. 3,782,481 makes the device unsuitable for a rotary joint which is user-moved since the user would find his region of motion severely restricted. The reference, therefore, used a drive motor, the use of which is unnecessary and, in fact, highly undesirable in the present invention. A further principal distinction between the present invention and this reference is that the sections of the present invention may rotate independently of each other.